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GEOREF RECORD

Tinderet Volcano, Kenya; an altered natrocarbonatite locality?

A. N. Zaitsev, T. Wenzel, T. Vennemann, G. Markl and Ray Macdonald
Tinderet Volcano, Kenya; an altered natrocarbonatite locality?
Mineralogical Magazine (April 2013) 77 (3): 213-226

Abstract

The Tinderet volcano (19.9 to 5.5 Ma), located within the Kavirondo rift in Kenya, contains blocks of carbonatite lavas with calcite, minor apatite, fluorite, spinel-group minerals, accessory perovskite and "plumbopyrochlore"; nyerereite is present as inclusions in the perovskite. At least four types of calcite are present in the carbonatite lavas; they differ in morphology, composition and origin. The dominant variety is secondary type-II calcite, which is enriched in sodium (up to 1.1 wt.% Na (sub 2) O) and strontium (up to 1.3 wt.% SrO). The spinel-group minerals are manganese-bearing and include Mn-rich magnetite, magnesioferrite and jacobsite. Oxygen isotope data for bulk carbonatite samples (delta (super 18) O=+16.2 per mil to +22.6 per mil VSMOW) support a low crystallization temperature for the secondary calcite. Petrographic, mineralogical and isotopic data indicate that the Tinderet carbonatites are similar to natrocarbonatites from the Oldoinyo Lengai and Kerimasi volcanoes that have altered and recrystallized to form calcite carbonatites. These data support the hypothesis that some of the Tinderet carbonatites were originally alkali-rich rocks which contained primary nyerereite.


ISSN: 0026-461X
EISSN: 1471-8022
Coden: MNLMBB
Serial Title: Mineralogical Magazine
Serial Volume: 77
Serial Issue: 3
Title: Tinderet Volcano, Kenya; an altered natrocarbonatite locality?
Affiliation: Saint Petersburg State Universityl, Faculty of Geology, Saint Petersburg, Russian Federation
Pages: 213-226
Published: 201304
Text Language: English
Publisher: Mineralogical Society, London, United Kingdom
References: 57
Accession Number: 2013-044374
Categories: Igneous and metamorphic petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 4 tables, sketch map
S00°04'00" - S00°04'00", E35°21'00" - E35°21'00"
Secondary Affiliation: Natural History Museum, GBR, United KingdomUniversitaet Tuebingen, DEU, GermanyUniversity of Lausanne, CHE, Switzerland
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, Copyright, Mineralogical Society of Great Britain and Ireland. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201328
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